[Bug-tar] Feature: posibility to use --new-volume-script with command

[Станислав]

It would be nice to have an ability to use 'command' for
--new-volume-script switch instead of 'script'

for example:
---
#!/bin/bash

tape_change () {
        echo change tape
}

tar -cvf -f /dev/nst0 --new-volume-script tape_change ...
---

Stanilsav